1. Field of the Invention
The present invention relates generally to an optical disk reproducing apparatus, and more particularly to an apparatus for discriminating between disks having different recording formats, for use in an optical disk reproducing apparatus.
2. Description of Related Art
Among conventional disk reproducing apparatuses, discrimination of disk types is typically performed between CD (Compact Disc) and LD (Laser Disc). The discrimination between CD and LD is possible by using different diameters of the CD and LD. More specifically, a pickup is first moved to a position outside the area of a CD and inside the area of a LD, the loaded optical disk is then rotated and determination is made as to whether or not the focus servo system locks. If it locks, the loaded disk is determined to be a LD, and if it does not lock, the disk is determined to be a CD.
On the other hand, in recent years there exists a strong demand for the increase of the recording capacity and the broadening of the compatibility among devices. To meet these demands, disks of the same size having different recording formats such as DVD (Digital Versatile Disk, or Digital Video Disk) are being developed.
A DVD has the same diameter as a CD, and its recording capacity is more than 4 gigabytes, which is far greater than the 640 megabyte CD recording capacity. The pit size and track pitch of a DVD are smaller than those of a CD because information is recorded at high density.
When attempting to reproduce a DVD in a player for CD reproduction, the reproduction of a DVD having high recording density is not possible because the diameter of the beam spot of the pickup is too large to read the pits on the DVD.
Furthermore, when locking of the focus servo system is tried when reproducing a DVD, that operation may cause a loss of control of the pickup moving mechanism because the tracking error signal is not properly produced when closing of the tracking servo system is attempted.